Re: [PATCH bpf-next v2 1/2] bpf, arm64: Remove redundant bpf_flush_icache() after pack allocator finalize

Breno Leitao
2026-04-15T12:38:16Z

On Mon, Apr 13, 2026 at 12:11:08PM -0700, Puranjay Mohan wrote:
> bpf_flush_icache() calls flush_icache_range() to clean the data cache
> and invalidate the instruction cache for the JITed code region. However,
> since commit 1dad391daef1 ("bpf, arm64: use bpf_prog_pack for memory
> management"), this flush is redundant.
>
> bpf_jit_binary_pack_finalize() copies the JITed instructions to the ROX
> region via bpf_arch_text_copy() -> aarch64_insn_copy() -> __text_poke(),
> and __text_poke() already calls flush_icache_range() on the written
> range. The subsequent bpf_flush_icache() repeats the same cache
> maintenance on an overlapping range, including an unnecessary second
> synchronous IPI to all CPUs via kick_all_cpus_sync().
>
> Remove the redundant bpf_flush_icache() call and its now-unused
> definition.
>
> Fixes: 1dad391daef1 ("bpf, arm64: use bpf_prog_pack for memory management")
> Acked-by: Song Liu <song@kernel.org>
> Signed-off-by: Puranjay Mohan <puranjay@kernel.org>

Acked-by: Breno Leitao <leitao@debian.org>